Question

A cone has a circular base, a perpendicular height equal to 21cm, and a semi-vertical angle of 30degrees. Calculate the slant height of the cone. Find the area of its base.(take pie to be 22/7)

Answer 1

if the slant height is s,
21/s = cos 30°

similarly, the radius r of the base is
r/21 = tan 30°

and, naturally, the area of the base
a = <b>pi</b> r^2

Answer 2

Pi r^2

Answer 3

solve it complete